1. Field of the Invention
Vesicles, which are so-called "liposomes" consisting of phospholipid bilayers, can be prepared by dispersing a lipid in an aqueous solvent. The liposomes can be useful as a drug-carrier for the administration to subjects if a drug is contained in aqueous compartments in liposome. The present invention relates to processes for preparing liposome compositions containing clinically active ingredients.
2. Prior Art
A process to prepare liposome compositions is disclosed in JPN Unexam. Pat. Pub. No. 53-142514 where the liposome compositions which have been formulated with phospholipid, active ingredient, and adjuvants are freeze-dried for stable storage.
Processes to prepare highly safe liposome compositions are also disclosed in JPN Unexam. Pat. Pub. Nos. 57-82310 and 57-82311 where freeze-dried vesicles are prepared with no organic solvent and are formulated into liposome compositions by the use of an aqueous medium containing any active ingredient.
On the other hand, a process is disclosed in the JPN Unexam. Pat. Pub. No. 58-152812, wherein SUV (small unilamella vesicles) or LUV (large unilamella vesicles) are prepared by dispersing a special phospholipid in an aqueous medium having a specific pH-value.